Parallax 250 HD Installed and Working!

Man this thing is a beast. Had to install it in several pieces with only a minimum of bodily injury.

It's a Parallax 250 HD Observatory mount. Solid. Solid. Solid. I've finally a mount to do the D&G 11" justice. So far the AP GOTO system seems fine but true to the "curse" , there have been clouds ever since installation last weekend so it's not exactly dialed in yet.

Ralph and Max, I really don't know the damping times yet as I've not had time really to use it due to weather. However, by just nudging it, RA seems very well damped, at least as good as the Byers Series II is. There is a bit too much backlash in DEC right now so that when DEC is balanced it can bounce around a bit. I need to snug the worm up against the gear a bit more. Adjustments like that seem easy. I can turn the RA very easily with my finger tips on the spur gears (It always amazes me to be able to move the 370 + pounds of scope, DEC castings, shafts and counter weights with just my finger tips). I'll adjust the worm on the DEC axis so that there is little backlash but still easily moves with the fingers as well and I'll probably leave a small imbalance in DEC to always load the gear train.

Before was a Byers Series II, which is now sitting on the observatory floor covered. For a moment the Parallax RA unit was sitting next to the Byers mount on the floor prior to me hoisting it up to the pier. I should have taken a picture as the Parallax RA assembly is bigger and weighs more than the entire Byers mounts...and the Byers is NO slouch, just lacks goto capability.

The lens is a D&G 11" F12. The pier is a two piece pier, with the lower, concrete pier 29" tall and the steel, upper pier bolted to it 60" tall. There is now an adapter plate/wedge that goes between the top of the steel pier and the bottom plate of the Parallax mount that lets me adjust the alt/azimuth of the mount. It adds 2" overall.

Mmm, currently I have on the drawing table a 300mm f/10 (to be also stopped-down as a 250 f/12), and I had been considering a mount with 70mm solid steel axes (60mm in Dec) and 270mm wheels in both axes... 4.1 teeth/cm (sorry for the metrics)...

Maybe I am underestimating the torque.

You have there 15" in RA and 11.3" in Dec, right? How many teeth, if I may ask?And your axes...?!

11" f12 GOTO refractor... that's obscene! I look forward to your pointing results. I imagine such a setup would benefit from a pointing model. I wonder what errors meridian flip will introduce on such a massive OTA.

I fully suspect there is some flex and non-orthogonality in my scope, almost certainly some from the rotating rings alone. I guess I'll see about the pointing accuracy. If anything, I can use the "Tour" mode since everything will be visual but I would like fairly accurate go-to's without having to fiddle around.

I'm prepared, if necessary, to go to third party pointing and modeling software. Any suggestions?